Method and apparatus for forming and applying terminals

ABSTRACT

A method and apparatus for sequentially preforming and applying electrical terminals includes a cutting, bending and crimping die set assembly which receives a substantially flat, precut strip stock and simultaneously crimps a terminal to a lead wire, cuts this terminal free from the strip stock, preforms the wire grip elements of the next succeeding strip terminal, and, during these operations, restrains the free terminal being crimped against motions.

Waited States Patent Inventors Constantine George Mates lElmhurst; Herbert G. Burkert, Crystal Lake, both of I11. Appl. No. 878,714 Filed Nov. 21, 1969 Patented Dec. 21, 1971 Assignee Thomas & Belts Corporation Elizabeth, NJ.

METHOD AND APPARATUS FOR FORMING AND APPLYING TERMINALS 8 Claims, 7 Drawing'Figs.

US. Cl 1. 29/628, 29/203 D lnt.Cl II0lr43/04 Field of Searc 29/628, 630

A, 203 D, 203 DT m1 mmms [56] References Cited UNITED STATES PATENTS 2,393,355 1/1946 Eppler et al. 29/628 3,101,765 8/1963 Batcheller 29/203 D X 3,473,219 10/1969 Randar et a1. 29/630AX 3,550,239 12/1970 Rider 29/203 D X Primary Examiner-Thomas H. Eager Attorney-Thomas M Marshall METHOD AND APPARATUS FOR FORMING AND APPLYING TERMINALS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method and apparatus for preforming electrical terminals and applying them by crimping to wire conductor segments in a continuous manner.

2. Description of the Prior Art U.S. Pat. No. 3,101,765, issued on Aug. 27, 1963 to the assignee of this invention, describes a machine for crimping terminals on wires, the terminals being of the type that are preformed from elongated metal strips, with each terminal being joined by a small neck of metal that is cut off during the application process to produce the final work product, namely a single terminal applied to a wire conductor. The instant invention is in the same field and constitutes an improved process and machine for accomplishing the same end result, with improved efiiciencies.

A problem found to occur with the preformed terminal strips used in the process described in the patent referred to just above was that the completely preformed terminals did not handle well when they were stored in roll form, essentially because the upturned grips, which are eventually crimped to the wire insulation and stripped conductor, tended to become snagged with themselves or the machinery. Also, the preformed strips, when coiled in roll form for use in these crimping machines, were rather bulky and unstable, again due to the presence of the upturned wire grips which were necessary for the crimping operation. What became desirable was a method and machine that could start with a generally flat preformed strip, that is, a strip comprising terminals preformed only to the extent that the wire grips were not upturned, and, before final assembly, could perform the upturning of the wire grips and cut off the crimped terminal from the remainder of the strip. This process needed to be continuous, and a method of firmly retaining the terminal being crimped in place during the final assembly and cutoff operation was desirable so as not to require the machine to handle and index loose terminals during the final operating steps of the assembly process. Furthermore, the machinery for accomplishing these objectives needed to be flexible enough to accommodate various sized terminals for crimping to various sized wires.

SUMMARY OF THE INVENTION The present invention generally relates to a machine for accomplishing a process of preforming wire and insulation grips on terminals supplied from a continuous strip stock, and crimping the terminals to the ends of stripped wire segments, all in a continuous manner. The machine basically comprises a fixed lower die set and a reciprocating upper die set which cooperates with the lower die set to receive precut terminals in strip form and, simultaneously and in a single step, cut a single terminal from the strip end, hold it in place while it is crimped to a conductor wire, and preform the wire grips of the next terminal on the strip to prepare it for the cutoff and crimping step in the next cycle of operation. Upon completion of the cut, crimp and preform operation just described, the die set is separated, the crimped terminal assembly is removed, the now completely preformed terminal is advanced to the crimping die, the next terminal is advanced to the grip preform die, a stripped wire is inserted in the crimp area, and the die set closes, repeating the simultaneous cutoff, crimp and preform operation. The die sets are multisegmental and the individual segments may be varied in size and spacing to accommodate various sized terminals and wire conductors. The terminal strips may be precut and in generally flat form prior to being fed to the machine of the present invention, thereby simplifying the handling, storing and feeding problems associated with the fully preformed terminals. The crimping machines of the type described in the preceding description of the prior art can generally be readily converted for use in accordance with this invention so as not to require expensive retooling costs. The present invention further obviates the necessity of handling loose terminals within the crimping machine, other than simply to hold the individual free terminals fixed during the crimping operation, a standard procedure associated with most crimping operations, regardless of the machine used, but here accomplished simultaneously with a cutoff, preform, and crimp operation in a unique manner.

A preferred embodiment of the present invention is described in full below, in conjunction with the accompanying drawing. The novel features of the invention are set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a precut and partially preformed terminal strip used in accordance with this invention;

FIG. 2 is an elevational, cutaway, representational view of a machine including a die set of this invention and preparatory to preforming a first preforming operation on a strip terminal;

FIG. 3 shows the terminal grip preforming die of FIG. 2 in operation;

FIG. 4 shows an end view of a preformed strip terminal immediately after the FIG. 3 operation;

FIG. 5 shows the preformed strip terminal advanced to the crimping die and before the cutoff operation;

FIG. 6 shows the die set of FIG. 2 performing a complete cutoff, crimp and preform operation on continuous strip ter' minals; and

FIG. 7 shows a sectional end view of the crimping die taken along line 7-7 in FIG. 6 during a crimping operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now the the drawings, FIG. 1 shows a precut, partially preformed terminal strip 10 used in conjunction with the process performed by the machine embodied by the present invention. The strip 10 comprises a series of terminals 12 joined together by reduced neck portions 14, and precut from relatively thin sheet metal strip stock so as to include grip tongues 16 and 18 for respectively engaging the insulation and stripped conductor of a lead wire to which the terminal 12 is to be secured by a crimping operation. The tongues l6 and 118 can be a variety of forms, but for the sake of simplicity, and clarity of depiction, they are shown here to be simply rectangular in shape and separated by a slit 20, the width of which is exaggerated somewhat in the drawings. At the end of each terminal 12 opposite the tongues 16, 18 is formed the desired configuration of male or female contact section; in this case, rolled flanges 22 form the desired female contact portions of each terminal. Alternatively, the terminal 12 may be in the form of a splice terminal for crimping two wire leads. Furthermore, it will be readily appreciated that various size terminals can be formed in strips similar to strip Ml, these further having various sized tongue sections for accommodating different wire sizes to which they are to be crimped. The neck portion 114 obviously will be cut off from between terminals during the final forming and assembly operations to be described momentarily; suffice it to say for the moment that this neck portion 1.45 constitutes the only scrap material of the strip stock illustrated in FIG. l, and can be varied in length and breadth to suit various requirements.

In FIG. 2, there is illustrated, somewhat schematically for the sake of clarity, apparatus embodying the present invention for preforming and applying electrical terminals 112 to wire leads. Essentially, the assembly shown comprises an upper and lower die set 24 and 26, respectively, the upper die set 24 being joined together for simultaneous movement up and down to coact with the lower die set 26, this being represented by line 28 and arrows 29 which depict unitary motion of the upper die set 24. The lower die set 26 is held relatively fixed within a suitable machine frame or base 30.

The upper die set 24 includes a cutoff blade 32, a crimping die 34, a male bending die 36, and a resilient holddown pad 38 which is shown biased downwardly by spring 40 in this case to illustrate the fact that holddown pad 38 can slide somewhat in a vertical plane parallel to the plane of motion of die set 24, and with respect particularly to blade 32. Crimping die 34 is generally conventional in form and includes a female bending form 40 for crimping the wire grip portions of terminals over the wire leads, as will be brought out more fully below, while the male bending die 36 simply includes a suitable male bending form 44 at its lower working end. The entire die set assembly 24 can be formed compactly, with each of the elements in relatively contiguous relationship in accordance with accepted practice in this field, and are preferably multisegmental in form to enable simple adjustment of tolerances, variation of spacing between die section, and replacement of worn parts. The upper, moveable die set 24 usually is mounted to a single ram unit (not shown) which provides the actuating force for moving and applying pressure to the die set during operation of the tool of this invention.

The lower die set 26 comprises a crimping and cutofi anvil 46 having a female crimping die form 48 at its forward end and a first cutoff or anvil edge 50 at its rearward end; a fixed die block 51 spaced rearwardly from the crimping and cutoff anvil, the die block having a forward edge 52 which serves as a second cutoff edge or anvil and a rearward edge 53 which serves as a fixed portion of the grip bending die of the assembly; and a moveable grip bending die pad 54 having a female bending form 56 at its forward end. The crimping form 48 and the cutoff anvil 50 could be separated structurally, if desired, from each other; that is, each of these parts could be attached to a separate unit within the lower die set if this were deemed to be more practical. They are shown here, of course, as different parts of a single die block 46. The moveable die pad 54 is shown here to be normally biased upwardly by spring 58, and pivotally secured to machine base 30 as at 60.

Considering now the operation and functioning of the elements described thus far, and with reference to FIG. 2, the machine is shown about to perform a first operation on a terminal strip 10 which has been advanced to a position where the grip tongues of the forwardmost terminal are placed just between the grip preform die set 36 and 54, and die block 51. It should be borne in mind that FIGS. 2, 3, and 6 are sectional views taken along a line that would longitudinally split the terminal strip along line AA as shown in FIG. 1, and for this reason only tongue 16 of the terminal is visible in these views.

Strip 10 having been advanced to the position shown in FIG. 2, upper die set 24 is lowered to the position of FIG. 3 where the grip tongue 16 (and tongue 18, not shown here) is bent to an upstanding position between the upper die form 44, the lower die pad form 56 and the rearward edge 53 of the fixed die block 51. The lower bending die pad 54 is seen to be moveable downwardly with respect to fixed die block 51 to accomplish the bending operation on the grip tongue 16 (and 18, of course). The interrelationship of upper and lower die sets and cutting blade is partially illustrated in FIG. 3, but will be more fully described in connection with the FIG. 6 view discussed below.

FIG. 4 illustrates an end view of the terminal 12 at the completion of the bending operation shown in FIG. 3, the terminal 12 now being completely preformed with grips I6 and 18 bent to an upright position preparatory to the final crimping operation when the grips will be secured to the conductor wire and the terminal 12 severed from the strip 10.

Upon completion of the grip tongue bending operation shown in FIG. 3, the upper die set 24 is raised, and the strip 10 is indexed forwardly as indicated by arrow 62 to a position where the forwardmost grip section 16 lies between the crimping die forms 34-46, and specifically within the cavity 48 of the lower die. This places the neck section 14 of the strip 10 directly beneath cutoff blade 32 and between the first cutofi' edge 50 of anvil 46 and the second cutoff edge 52 of fixed block 51. The proportions of die sets 24-26 and strip terminals 12 are such that, with the forwardmost terminal properly positioned in the crimping area (beneath crimp die 34), the neck 14 is situated in the cutoff area (beneath blade 32) and the tongues 16 and 18 of the next succeeding terminal 12 are in the grip bending area (beneath die 36).

With the strip 10 now in position as shown in FIG. 5, a conductor wire 64 stripped of its insulation 66 over a portion of its end is placed in position within the hollow of bent grips I6, 18 (see FIGS. 6 and 7) and the upper die set 24 again closes against the lower die set 26. FIGS. 6 and 7 show these dies, as they approach the closed position performing, in order of occurrence. the cutoff of neck 14 by blade 32, the crimping of tongue elements 16 and 18 about the insulation 66 and wire 64, respectively, of a conductor lead, and substantially simultaneously with the crimp operation, the bending upwardly and preforrning of grip elements 16 and 18, with the free forwardmost terminal being crimped being held down at its rearward end by resilient holddown pad 38. The provision of a certain amount of lost motion between the upper die set 24 and the pad 38 enables the pad to resiliently clamp the forward terminal 12 at its rearward edge while the die set 24 is still progressively closing and applying cutoff and forming pressures to the strip terminals being cut, crimped and bent.

Upon completion of the operation shown in FIG. 6, the upper die set 24 is raised, the forward terminal, now crimped to its lead wire, is removed, and the strip 10 is once again indexed to the position shown in FIG. 5. The cycle is then repeated in continuous fashion to perform terminal forming and crimping operations simultaneously on the forwardmost and next succeeding strip terminals, with an added provision included of a resilient holding means for restraining the terminals being crimped in a fixed position during the crimp operations.

We claim:

1. Apparatus for preforming the wire grips of terminals supplied from precut strip stock and applying the terminals to lead wires comprising:

a pair of upper and lower die sets for engaging the forwardmost and next succeeding terminals on the strip, said die sets including:

a cutoff blade for severing the forwardmost terminal from the strip; a crimping die and anvil spaced forwardly of the said blade for crimping the grip of the forwardmost terminal to a lead wire; a grip bending die; the grip bending die and pad spaced rearwardly of the said blade for bending the grip of the next succeeding terminal on the strip to an upright position preparatory to the crimping operation; and the cutoff blade reaching its operative cutting position before said crimping and bending dies during each cycle of operation.

2. The apparatus of claim 1 further including:

indexing means for advancing the terminal strip between die set closings to place the terminal having its grip portion bent on the previous die closing in proper position beneath the crimping die preparatory to the next die closmg.

3. The apparatus of claim 1 further comprising:

holddown means for holding the forwardmost terminal fixed relative to the crimping anvil during both the terminal cutofi and crimp operations.

4. Apparatus for continuously preforming and applying longitudinally aligned precut strip terminals to lead wires comprising:

an upper die set assembly including:

a cutoff blade;

a crimping die spaced forwardly of the cutoff blade; and

a terminal grip bending male die spaced rearwardly of the cutofi blade;

a lower die set assembly including:

a first cutoff anvil;

a crimping anvil spaced forwardly of the first cutoff anvil; a fixed die block spaced rearwardly of the first cutoff anvil, the block having a forward edge portion constituting a second cutoff anvil, and a rearward edge portion constituting a fixed section of a bending die; and a moveable, female, grip bending die pad spaced immediately rearwardly of the rearward edge of said fixed die block; and said upper and lower die sets coacting vertically in such a manner that in the die closed position, the cutoff blade extends between the first and second cutofi' anvils; the upper crimping die fits over the lower crimping anvil; and the upper terminal grip bending male die engages the lower, moveable, female grip bending die pad to cause lowering of the latter relative to the rearward edge of the lower fixed die block.

5. The apparatus of claim 4 further including:

a holddown pad which is associated with and coacts with the upper die set in such a manner that in the die closed position the said holddown pad engages the top of said first cutoff anvil, the pad being located forwardly of the cutoff blade and mounted so as to be capable of slight lost motion relative to the upper die set over a small range of movement of said upper die set as the die closed position is approached.

6. The apparatus of claim 5 wherein at least a portion of said holddown pad is resilient, that portion being the one coming in contact with the first cutoff anvil in the die closed position.

7. The method of sequentially preforming the wire grips of terminals and applying the terminals to lead wires comprising:

a. supplying substantially flat, precut strip terminals to a cutting, bending and crimping die set assembly;

i. the strip terminals being joined longitudinally to each other by strip stock material and having grip tongues precut from the strip stock in a desired pattern;

ii. the die set assembly including a cutting member, a grip bending member located behind the cutting member; the crimping member and bending member being spaced apart longitudinally a distance equivalent to the distance between terminal grips;

b. preforming the wire grips of the forwardmost strip terminal by bending them upright in the grip bending member of the die set assembly;

c. advancing the strip of terminals forwardly in the die assembly until the preformed gn'ps of the forwardmost terminal overlap the crimping member of the die set assembly;

d. supplying a lead wire to the die assembly in the area of the preformed, upright terminal grips;

e. simultaneously severing the preformed forwardmost terminal from the strip by cutting the strip stock material between the forwardmost and next succeeding terminal by means of the cutting member of the die set assembly, crimping the preformed terminal grips to the lead wire by means of the crimping member of the die set assembly and bending upright the wire grips of the terminal nent succeeding the forwardmost terminal being crimped by means of the bending member of the die set assembly;

f. removing the crimped terminal and wire lead from the die set assembly; and

g. repeating steps (C) through (F) for the desired number of cycles.

b. The method of claim 7 wherein the die set assembly of step (a)(ii) includes a holddown pad forward of the cutting member, and step (e) further includes holding down the terminal being crimped by means of a holddown pad of the die assembly during the crimping operation. 

1. Apparatus for preforming the wire grips of terminals supplied from precut strip stock and applying the terminals to lead wires comprising: a pair of upper and lower die sets for engaging the forwardmost and next succeeding terminals on the strip, said die sets including: a cutoff blade for severing the forwardmost terminal from the strip; a crimping die and anvil spaced forwardly of the said blade for crimping the grip of the forwardmost terminal to a lead wire; a grip bending die; the grip bending die and pad spaced rearwardly of the said blade for bending the grip of the next succeeding terminal on the strip to an upright position preparatory to the crimping operation; and the cutoff blade reAching its operative cutting position before said crimping and bending dies during each cycle of operation.
 2. The apparatus of claim 1 further including: indexing means for advancing the terminal strip between die set closings to place the terminal having its grip portion bent on the previous die closing in proper position beneath the crimping die preparatory to the next die closing.
 3. The apparatus of claim 1 further comprising: holddown means for holding the forwardmost terminal fixed relative to the crimping anvil during both the terminal cutoff and crimp operations.
 4. Apparatus for continuously preforming and applying longitudinally aligned precut strip terminals to lead wires comprising: an upper die set assembly including: a cutoff blade; a crimping die spaced forwardly of the cutoff blade; and a terminal grip bending male die spaced rearwardly of the cutoff blade; a lower die set assembly including: a first cutoff anvil; a crimping anvil spaced forwardly of the first cutoff anvil; a fixed die block spaced rearwardly of the first cutoff anvil, the block having a forward edge portion constituting a second cutoff anvil, and a rearward edge portion constituting a fixed section of a bending die; and a moveable, female, grip bending die pad spaced immediately rearwardly of the rearward edge of said fixed die block; and said upper and lower die sets coacting vertically in such a manner that in the die closed position, the cutoff blade extends between the first and second cutoff anvils; the upper crimping die fits over the lower crimping anvil; and the upper terminal grip bending male die engages the lower, moveable, female grip bending die pad to cause lowering of the latter relative to the rearward edge of the lower fixed die block.
 5. The apparatus of claim 4 further including: a holddown pad which is associated with and coacts with the upper die set in such a manner that in the die closed position the said holddown pad engages the top of said first cutoff anvil, the pad being located forwardly of the cutoff blade and mounted so as to be capable of slight lost motion relative to the upper die set over a small range of movement of said upper die set as the die closed position is approached.
 6. The apparatus of claim 5 wherein at least a portion of said holddown pad is resilient, that portion being the one coming in contact with the first cutoff anvil in the die closed position.
 7. The method of sequentially preforming the wire grips of terminals and applying the terminals to lead wires comprising: a. supplying substantially flat, precut strip terminals to a cutting, bending and crimping die set assembly; i. the strip terminals being joined longitudinally to each other by strip stock material and having grip tongues precut from the strip stock in a desired pattern; ii. the die set assembly including a cutting member, a grip bending member located behind the cutting member; the crimping member and bending member being spaced apart longitudinally a distance equivalent to the distance between terminal grips; b. preforming the wire grips of the forwardmost strip terminal by bending them upright in the grip bending member of the die set assembly; c. advancing the strip of terminals forwardly in the die assembly until the preformed grips of the forwardmost terminal overlap the crimping member of the die set assembly; d. supplying a lead wire to the die assembly in the area of the preformed, upright terminal grips; e. simultaneously severing the preformed forwardmost terminal from the strip by cutting the strip stock material between the forwardmost and next succeeding terminal by means of the cutting member of the die set assembly, crimping the preformed terminal grips to the lead wire by means of the crimping member of the die set assembly and bending upright the wire grips of the terminal next succeeding the forwardmost terminal being crimped by means oF the bending member of the die set assembly; f. removing the crimped terminal and wire lead from the die set assembly; and g. repeating steps (C) through (F) for the desired number of cycles.
 8. The method of claim 7 wherein the die set assembly of step (a)(ii) includes a holddown pad forward of the cutting member, and step (e) further includes holding down the terminal being crimped by means of a holddown pad of the die assembly during the crimping operation. 